Just serviced my focus and sold it to a friend. Did an oil service using recommended castrol. They’ve sent me a video of the clicking noise coming from the car. The noise is only when the car is in idle not when driving or when the engine is being revved. Paperwork shows that the engine mount was changed 4000 miles ago. The noise was coming from the car before the service but the car is only on 40,000 miles and after I had serviced it the noise had gone down significantly, but now that he started to drive it the noise has come back not too sure what it is. Any advice as I’m gonna have to refund some of the money hoping it’s not too expensive of a fix